Our objective is to purchase a state-of-the-art cardiovascular (CV) ultrasound imaging system for the University of Wisconsin Atherosclerosis Imaging Research Program (UW AIRP), which will function as a long-term, shared resource for NIH-funded investigators at the UW School of Medicine and Public Health (UW SMPH). Specific aims include: (i) Aim 1: To improve the productivity of CV research at the UW SMPH by making state- of-the-art ultrasound imaging more accessible to federally-funded investigators, (ii) Aim 2: To enhance the ability of these investigators to perform clinical and animal studies of CV structure and function, and (iii) Aim 3: To foster the development of new CV research studies that most efficiently use the intellectual, personnel, and instrumentation resources at the UW SMPH. The importance of research into the mechanisms and treatment of CV disease is emphasized by the observations that approximately 2200 Americans die of CV disease each day and that CV disease is the leading cause of death in the United States. CV ultrasound research at the UW SMPH primarily is conducted in the UW AIRP, a core ultrasound reading, scanning, and training laboratory for research studies that investigate atherosclerosis burden and CV risk. In April, 2005, the UW AIRP Director, Dr. James Stein, received a NCRR S10 grant (RR 021086) to purchase a Siemens Acuson Sequoia C512 ultrasound system. Since 2005, ultrasound technology has improved dramatically. The Sequoia has several limitations that risk reducing the research productivity of the UW AIRP and its users. Also, the Sequoia is approaching end-of-life and in 2014 no longer will be serviced by Siemens. Because of these considerations, the Sequoia system needs to be replaced. This revised application proposes purchase of a state-of-the-art Siemens Acuson S2000 cardiovascular ultrasound system with modern software and transducer technology. This will facilitate and enhance the scientific quality of several NIH-supported research projects. The research studies that will use the new shared ultrasound system seek to understand the physiological consequences and treatment of CV disease risk factors and conditions, including atherosclerosis, aortic aneurysm, tobacco use, sleep-disordered breathing, hypertension, pulmonary hypertension, human immunodeficiency virus, and heart failure. The Major users group consists of 5 investigators with 5 R01- and 1 U01-funded grants. The Minor users group consists of 4 investigators with 3 R01-, 1 R21-, and 1 K23-funded grants. These investigators request this instrument to help them achieve their grants' specific aims. The ultrasound equipment needed for these studies does not exist in the UW SMPH outside of the UW AIRP and our current system is approaching obsolescence. The only other option is clinical equipment that must be borrowed or time purchased from an oversubscribed clinical laboratory, which is expensive and inconvenient. Exceptionally strong institutional support and technical expertise assure that the requested equipment will be operable immediately and be highly productive at UW.